What happened today in France's presidential race

French presidential election candidate for the far-right Front National (FN) party Marine Le Pen (R) delivers a speech during a campaing rally at the Puybonnieux farm in Pageas, near Limoges, on April 13, 2017

With 10 days left until the first round of France's presidential election, Marine Le Pen's campaign headquarters was hit by an arson attempt and pressure built on President Francois Hollande to anoint a successor.

A police source said the fire was "probably criminal", adding that the graffiti slogan "FN vs KLX" was found nearby.

A group calling itself "Fight Xenophobia" contacted AFP to claim the attack, which it said was carried out with petrol bombs.

Le Pen, 48, is running neck-and-neck in voter surveys with centrist candidate Emmanuel Macron ahead of the April 23 first round. The 39-year-old Macron is currently tipped to win the decisive May 7 runoff vote.

- Macron goads Hollande -

With his former mentor, President Francois Hollande, refusing to divulge whom he will back in the election, Emmanuel Macron said he did not think voters were eager to know.

"I don't think that is what our compatriots are waiting for," said Macron, who quit the Socialist government last year to launch his independent presidential bid.

The deeply unpopular Hollande, who dithered until December before deciding not to seek re-election, now faces a quandary.

Should he back a likely winner in Macron, as his former prime minister Manuel Valls has done? Valls also deserted Hollande to mount his own bid for the presidency, losing to Macron in a January primary.

Or should Hollande plump for the Socialist candidate, Benoit Hamon, who led a rebellion last year against his labour reforms?

The 48-year-old is currently trailing in fifth place in the polls.

The outgoing president told the weekly Le Point, out Thursday, that he would name his choice after the April 23 first round.

While he hinted at supporting Macron -- saying the French want "new measures to build on what I have done" -- he also suggested his former protege's meteoric rise was the result of a "confluence of circumstances".

He also had bitter words for Hamon: "Those in the government who railed against my policies have reaped no glory since."

- Top US banker not nervous -

Wall Street's most powerful banker, JPMorgan Chase chief Jamie Dimon, told AFP he was not nervous over developments in the French election campaign.

Analysts blamed a slight dip on Wall Street early Thursday to jitters over Le Pen's strengthening poll numbers, even though pollsters are unanimous that she cannot win in May, whoever she faces in the runoff.

"The French people are going to decide who their president is going to be and whoever that is, JPMorgan Chase will deal with it and will be fine," he said.

Dimon also said he had his "own personal views on who that should be... but I'm not going to go into that for the press."